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P. S. TICE CARBURETOR June 5, 1934.

Original Filed Sept. 9, 1929 Patented June 5, 1934 CARBWETOR Percival S.Tice, Chicago, m, assignmto Stewart- Warner Corporation, Chicago, 111.,a corporation of Virginia Original application September 9, 1929, SerialNo.

Divided and this application October 25, 1930, Serial No. 491,130

4 Claims. (01. 15847) This application is a division of my pendingapplication Serial No. 390,602, filed September 9, 1929, the purpose ofthe invention to be defined in this divisional application being toprovide 5 an improved fuel feeding system for internal combustion enginecarburetors. It consists in the elements and features of constructionshown and described as indicated in the claims.

In the drawing Figure 1 is a side elevation of a carburetor constructionembodying this invention.

Figure 2 is a partly sectional elevation of the side opposite that seenin Figure 1, section being made through the fuel accumulating chamberand fuel mixture intake passage, axial with respect to the latter.

The carburetor construction shown in the drawing comprises a bodymember, A, having an air and fuelmixture conduit, 20, leading from theair inlet, 21, at which the air enters, substantially horizontally witha 90 degree bend upwardly to the upper end of said body member. at whichthe latter is adapted for mounting at the engine intake for dischargeinto the intake manifold, a choke valve, 23, being provided at theentrance, and the throttle valve, 24, being mounted at the upperdischarge end.

In the upwardly extending part of said conduit there is mounted aVenturi sleeve, 26, having formed integrally with it a nozzle member,27, of special construction, the details of which are not part of thepresent invention. The body member comprises also a fuel chamber, 30,extending adjacent the upwardly extending part of the air and fuelmixture conduit at the side opposite the air inlet and choke valve, saidchamber extending down around and under the convex side of the 90 degreebend mentioned.

The fuel chamber extending to the lower end of the body member, A, isclosed at that end by a bottom skeleton cap, 45, conical in general formwith its conical cavity at the upper side. and having a marginalexteriorly protruding flange mated in dimensions with the lower end 46of the body member for clamping between said lower end of the flange andsaid body member a flexible diaphragm, 4'7, which thereby becomeseffectively the capacity-limiting bottom of the fuel chamber; and abovesaid diaphragm a damp- 59 ing plate, 48, which is a metal stampingflexed upwardly as seen at 48', at the central area within the clampedmargin, 48", and insulated from the body member, A, by an interposedpacking gasket 48".

The diaphragm, 47, has at its under side asheet metal disk, 49,reenforcing the diaphragm at a relatively large central portion of itsarea, limiting its ilexure to the annular area, 47, outside said centralreenforced area.

There is provided at the under side of the diaphragm a coil spring, 50,reacting between the metal disk, 49, and the diaphragm, 4'7, and anacfiusting screw, 51, which is screwed into the lower end of the bottomcap, 45, said spring being centered at its upper end upon the nut, 61,by which the disk, 49, is clamped to the diaphragm, the lower end of thespring being centered upon the reduced upper end, 51, of the tensioningscrew, 51.

The damping plate, 48, has a central aperture, 48 affording restrictedaccess to the diaphragm, of the fuel in the stand pipe orlevel-governing chamber 30. Said damping plate carries an insulatingpost, 48, on the end of which there is secured one end of a lower springcontact member, 65, said contact members both extending into alignmentwith the axis of the diaphragm where they are provided with contactbuttons, 64", 65', respectively facing each other, the spring contactmember, 65, having a non-conductive pin, 65, projecting down through theaperture, 48, in the damping plate, 48, for restricting said apertureand for encounter with the diaphragm. 4'1, at the center of the latter.

The electric circuit in which the electro-magnetic pumping device,hereinafter described, is energized, comprises a current wire indicatedat 72 leading from a source of current indicated at 75 to a bindingscrew, '16, of which the threaded post, 77, is insulatedly mountedlaterally of the. body, A, at the lower end thereof and protruding intothe fuel chamber, 30, closely above the damping plate, 48, as seen inFigure 2, where the terminal of said insulated binding post is incontact with the end of the spring contact member, 65, with whichcontact is maintained by the resiliency of the end portion, 65 of saidcontact member which is suitably flexed for hearing against said bindingpost, as seen in Figure 2.

From the contact member, 64, the circuit is continued through aconductor, 66, hereinafter more particularly described.

From the foregoing it may be understood that in the intended operationthe accumulation of fuel in the stand pipe, 30, to a predetermineddegree of hydrostatic pressure determined by the adjustment of thespring, 50, will operate the diaphragm for separating the contacts, 64and 65, opening the energizing circuit of the electro magnetic pumpingapparatus, and interrupting 11 the fuel supply until the engineconsumption causes the fuel level in the chamber, 30, to be reduced,reducing the hydrostatic pressure on the diaphragm, whose spring, 50,will thereupon react and cause the diaphragm to move the contact, 65*,for closing the circuit.

the construction shown, the upper contact member, 64, is a bi-rnetallicbar comprising two strips of metal having different co-eihcients ofexpansion and contraction under temperature change, the lower striphaving the higher coefiicient so that the bar 64 tends to be flexedupwardly at the end carrying the contact button, 64, upon rise oftemperature due to the fuel in the chamber, 30, becoming heated in therunning of the engine.

primary purpose of this feature or" the construction is to cause thehydrostatic pressure for fuel delivery to be somewhat greater when thefuel is cold than when it is hot which is desirable for the reason thata richer mixture is needed when starting with the engine, and therebythe fuel, cold, than when the engine is warmed up by running and thefuel is correspondingly e heated.

In modern engines, the engine becomes heated so quickly after startingthat the normal condition may be properly considered to be the heatedcondition, and the above described features of the carburetor structuredetermining the normal depth of fuel in the carburetor fuel chamber aredesigned to ensure that depth with the engine heated.

Without the control afforded by the thermoresponsive contact carrier,64., the level in the fuel chamber would be lower with the fuel cold andhigher with the fuel hot, which is the reverse of the requirement ofmodern engines on modern cars, in which the provision of automatictemperature controlled radiator shutters and the like, causes theproperly heated condition of the engine to be obtained so quickly at thestarting of the engine, that the normal condition for which the leveldetermining features are designed, is the heated and not the coldcondition; and the devices described afford the necessary correction oflevel from normal to higher than normal when the engine, and thereby thefuel, is cold, or below what may properly as above stated be consideredthe normal temperature.

Accordingly, the normal form and position of the contact carrier, 64,may be considered to be its condition and form when flexed upwardly asseen in Figure 2, for holding the contact button, 64 at a positionrequiring least hydrostatic pressure on the diaphragm in order toseparate the contact, 65*, from said contact, 64. And the abnormalcondition may be regarded as that at which the part, 64, is straight orslightly flexed downward.

This feature also serves a secondary, but not negligible, purposeconcerned with the increase of fluidity and reduction of viscosity whichis concurrent with rise in temperature of the fuel. By reason of theincrease of fluidity and reduction of viscosity which attend rise intemperature, the fuel will be discharged more freely, and so in greaterquantity, through a given passage which is restricted so as to causesubstantial friction when the fuel is hot than when it is cold.

And to maintain the desired uniformity of mixture, the pressure mustdecline as the temperature rises, which is the result of making thecontact-carrying member, 64, bi-metallic, so that rise of temperaturecauses the Contact butsleeper-s1 ton, 64 to move in the direction forearlier opening of the circuit, i. cl, opening with less depth of fuelin the fuel chamber;

Circuit connection to the upper spring contact member, 64, is made asabove mentioned by a circuit wire, 66, which is mounted rigidly in aconductive sleeve, which in turn is mounted in the post, 48 above whichsaid upper contact member is secured, the upper end of said sleeve beingpeened over the contact member, 64, for securing the latter on the postas above described. Said spring contact wire extends up in the chamber,30, and at the upper end is bent laterally, as seen at 66'", forprojecting into contact with a contact button, 80, pertaining to theelectric circuit in which is energized the fuel supply pump contained inthe casing, "B, wd by which the fuel is supplied to the carburetor. Theconstruction and operation of this electric pump is fully shown anddescribed in my said parent application, and no description of the sameis necessary for the understanding of the invention to which thisdivisional application is directed.

I claim:

1. hi a carburetor comprising a fuel accumulating chamber andelectrically energized pumping means for supplying fuel thereto, aswitching apparatus operable by the hydrostatic head of fuel to controlthe energizing circuit of the pumping means and having one of itscooperating circuit-making-and-breaking contact-carry- .ing memberslocated in the fuel accumulating chamber in position for exposure to thetemperature of the fuel content of the chamber, said member beingconstructed for response to change of temperature of the fuel to moveits contact in a direction toward or away from the other contact of saidswitching apparatus.

2. In a carburetor comprising a fuel accumulating chamber, electricallyenergized means for furnishing fuel to said chamber, means responsive tothe pressure of the fuel accumulating in the chamber for controlling theenergizing electric circuit, said means including atemperature-responsive contact-carrying member of a circuit-controllingswitch, said switch member being located in the fuel accumulatingchamber exposed to the temperature of the fuel content and adapted tocarry its contact out of circuitclosing position upon the temperaturederived from the fuel reaching a predetermined degree, saidtemperature-responsive switch member and the cooperatng switch memberbeing associated with the pressure-responsive element for breaking thecircuit by the movement of said pressureresponsive member upon thepressure exceeding a predetermined degree.

3. In a carburetor comprising a fuel accumulating chamber, electricallyenergized means for furnishing fuel to said chamber, a circuit in whichthe same is energized and a switch controlling said circuit, meansoperated by the hydrostatic pressure of the fuel accumulated in saidchamber beyond a predetermined depth for operating the switch incircuit-breaking direction for de-energizing the fuel furnishing means,the switch being located in the fuel accumulating chamber exposed to thetemperature of the fuel therein, and comprising a temperature-responsivecontact-carrying member arranged to be flexed by temperature change forcarrying its contact in circuit-breaking direction upon the temperatureexceeding a predetermined degree, one of the cooperating members of theswitch eing associated with the diaphragm for movement therebyrelatively to the other switch member in circuit-breaking direction uponthe diaphragm being flexed in circuit-breaking direction.

4. In a carburetor comprising a fuel accumulating chamber having aflexible diaphragm constituting part of its enclosing wall at thelowerpart of said chamber, means reacting resiliently on said diaphragmin opposition to the pressure of the fuel content of the chamber forresisting the outward flexing of the diaphragm and adapted to yield forpermitting such outward fiexure upon said pressure reaching apredetermined

